Foul weather (25F - 45F temperatures, NW wind 15 - 25mph) battery performance is my primary concern. I vaguely understand this subject. I will journal information as my understanding grows.
The question I hope we can converge on an to answer, is:
The starting points:
This subject depresses me. My hope was to use an electric bike in nasty Denver weather. November through March are the months most likely to have highest winds and lowest temperatures. I escape the harsh conditions by seeking shelter in low-lying bike paths. I really do not like these paths because they are slow. Too many dog-walking pedestrians who take up the entire bike path give-or-take 50 feet of extendable dog leash lines. Much less what I would like to do to the super aggressive dogs and comatose owners.
The last thing I want to do is get tangled in those lazy leash lines.
I will incrementally expand on this topic. I hope I have not reached a dead end in my search for an eBike. Bosch does not seem to advocate using their batteries below 50F. I am looking for a "foul-weather" bike. eBikes do not seem to be the foul-weather solution that I seek.
Glossary from Battery University:
The question I hope we can converge on an to answer, is:
- What makes for a good or poor performing foul weather battery pack, charger and battery management system.
- Rack mounted can be an enclosed, heated unit that is protected from direct wind.
- Large capacity. Optimal number of cells and series/parallel configuration?
- Charging process information easily accessed and battery health graphically presented.
- What is missing from existing systems that make them unreliable in foul weather, e.g., redundancy, chemistry, heater, fairing, etc...
- Is design appropriate?
- What role does the motor controller play, e.g., unsuitable power assistance levels for foul weather.
- Might eMTB power assist adapt better to foul weather?
The starting points:
- https://batteryuniversity.com/index.php/learn/article/discharging_at_high_and_low_temperatures
- https://batteryuniversity.com/index.php/learn/article/bu_803a_cell_mismatch_balancing
- * https://batteryuniversity.com/index.php/learn/article/how_to_prolong_lithium_based_batteries
- https://batteryuniversity.com/index.php/learn/article/battery_calibration
- https://batteryuniversity.com/index.php/learn/archive/the_smart_battery
- Smart battery fuel gauges: http://www.ti.com/download/aap/pdf/batt_mgmt_3q00.pdf
- https://batteryuniversity.com/index.php/learn/article/battery_test_equipment
- https://batteryuniversity.com/index..._604_how_to_process_data_from_a_smart_battery
This subject depresses me. My hope was to use an electric bike in nasty Denver weather. November through March are the months most likely to have highest winds and lowest temperatures. I escape the harsh conditions by seeking shelter in low-lying bike paths. I really do not like these paths because they are slow. Too many dog-walking pedestrians who take up the entire bike path give-or-take 50 feet of extendable dog leash lines. Much less what I would like to do to the super aggressive dogs and comatose owners.
The last thing I want to do is get tangled in those lazy leash lines.
I will incrementally expand on this topic. I hope I have not reached a dead end in my search for an eBike. Bosch does not seem to advocate using their batteries below 50F. I am looking for a "foul-weather" bike. eBikes do not seem to be the foul-weather solution that I seek.
Glossary from Battery University:
- Cell reversal - Since the cells in a battery pack can never be perfectly matched, a negative voltage potential can occur across a weaker cell in a multi-cell pack if the discharge is allowed to continue beyond a safe cut-off point.
- Going empty first causes their strong brothers to overrun their feeble sibling to the point where a high load can push the weak cell into reverse polarity.
- Recharge cycling - will not significantly improve the capacity of the low-end cell, and the buyer should be aware of differences in capacity and quality, which often translate into life expectancy.
- Cell matching - according to capacity is important, especially for industrial batteries, and no perfect match is possible.
- Capacity tolerance - between cells in an industrial battery should be +/– 2.5 percent. High-voltage packs designed for heavy loads and a wide temperature range should reduce the capacity tolerance further. There is a strong correlation between cell balance and longevity.
- Passive balancing bleeds high-voltage cells on a resistor during charge in the 70–80 percent SoC curve;
- Active balancing shuttles the extra charge from higher-voltage cells during discharge to those with a lower voltage.
- Protection circuit - assures that serially connected cells do not exceed 4.25V/cell (most Li-ion) on charge and that disconnect when the weakest cell drops to 2.80V/cell or lower.
- The discharge disconnect prevents the stronger cells from pushing the depleted cell into reverse polarity
- Equalizing charge - a charge on top of a charge that brings all cells to full-charge saturation.
- Depth of Discharge - (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last.
- Battery analyzers serve as a valuable tool to calibrate a smart battery. An analyzer fully charges the battery and then applies a controlled discharge that provides the all-important capacity readings of the chemical battery. This discharge measurement is a truer reading than what coulomb counting provides by capturing past discharge events of the digital battery.
- impedance tracking - This is a self-learning algorithm that reduces or eliminates the need to calibrate. If calibration is required, however, several cycles instead of only one may be needed to achieve the same result as with a standard system.
- Max Error - The accuracy between the chemical and digital battery is measured by the Max Error.
- Full charge capacity (FCC), coulomb count that is hidden in the table among tons of other information. FCC can be used with reasonable accuracy to estimate battery SoH without applying a full discharge cycle to measure capacity.
- SMBus - is the most complete of all systems. It represents a large effort from the electronics industry to standardize on one communications protocol and one set of data. The Duracell/Intel SBS, which is in use today, was standardized in 1993.
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